form_field_validationUNIX Programmer's Maform_field_validation(3)NAMEform_field_validation - data type validation for fields
SYNOPSIS
#include <form.h>
int set_field_type(FIELD *field, FIELDTYPE *type, ...);
FIELDTYPE *field_type(const FIELD *field);
void *field_arg(const FIELD *field);
FIELDTYPE *TYPE_ALNUM;
FIELDTYPE *TYPE_ALPHA;
FIELDTYPE *TYPE_ENUM;
FIELDTYPE *TYPE_INTEGER;
FIELDTYPE *TYPE_NUMERIC;
FIELDTYPE *TYPE_REGEXP;
FIELDTYPE *TYPE_IPV4;
DESCRIPTION
The function set_field_type declares a data type for a given
form field. This is the type checked by validation func-
tions. The predefined types are as follows:
TYPE_ALNUM
Alphanumeric data. Requires a third int argument, a
minimum field width.
TYPE_ALPHA
Character data. Requires a third int argument, a
minimum field width.
TYPE_ENUM
Accept one of a specified set of strings. Requires a
third (char **) argument pointing to a string list; a
fourth int flag argument to enable case-sensitivity;
and a fifth int flag argument specifying whether a par-
tial match must be a unique one (if this flag is off, a
prefix matches the first of any set of more than one
list elements with that prefix). Please notice that the
string list is not copied, only a reference to it is
stored in the field. So you should avoid using a list
that lives in automatic variables on the stack.
TYPE_INTEGER
Integer data, parsable to an integer by atoi(3).
Requires a third int argument controlling the preci-
sion, a fourth long argument constraining minimum
value, and a fifth long constraining maximum value. If
the maximum value is less than or equal to the minimum
value, the range is simply ignored. On return the field
buffer is formatted according to the printf format
specification ".*ld", where the '*' is replaced by the
precision argument. For details of the precision
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form_field_validationUNIX Programmer's Maform_field_validation(3)
handling see printf's man-page.
TYPE_NUMERIC
Numeric data (may have a decimal-point part). Requires
a third int argument controlling the precision, a
fourth double argument constraining minimum value, and
a fifth double constraining maximum value. If your sys-
tem supports locales, the decimal point character to be
used must be the one specified by your locale. If the
maximum value is less than or equal to the minimum
value, the range is simply ignored. On return the field
buffer is formatted according to the printf format
specification ".*f", where the '*' is replaced by the
precision argument. For details of the precision han-
dling see printf's man-page.
TYPE_REGEXP
Regular expression data. Requires a regular expression
(char *) third argument; the data is valid if the regu-
lar expression matches it. Regular expressions are in
the format of regcomp(3) and regexec(3). Please notice
that the regular expression must match the whole field.
If you have for example an eight character wide field,
a regular expression "^[0-9]*$" always means that you
have to fill all eight positions with digits. If you
want to allow fewer digits, you may use for example
"^[0-9]* *$" which is good for trailing spaces (up to
an empty field), or "^ *[0-9]* *$" which is good for
leading and trailing spaces around the digits.
TYPE_IPV4
An Internet Protocol Version 4 address. This requires
no additional argument. It is checked whether or not
the buffer has the form a.b.c.d, where a,b,c and d are
numbers between 0 and 255. Trailing blanks in the
buffer are ignored. The address itself is not vali-
dated. Please note that this is an ncurses extension.
This field type may not be available in other curses
implementations.
It is possible to set up new programmer-defined field types.
See the form_fieldtype(3) manual page.
RETURN VALUE
The functions field_type and field_arg return NULL on error.
The function set_field_type returns one of the following:
E_OK The routine succeeded.
E_SYSTEM_ERROR
System error occurred (see errno).
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form_field_validationUNIX Programmer's Maform_field_validation(3)SEE ALSOcurses(3), form(3).
NOTES
The header file <form.h> automatically includes the header
file <curses.h>.
PORTABILITY
These routines emulate the System V forms library. They
were not supported on Version 7 or BSD versions.
AUTHORS
Juergen Pfeifer. Manual pages and adaptation for new curses
by Eric S. Raymond.
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